AN EVALUATION STUDY FOR FIBRE ANALYSIS BY UV-VIS MICROSPECTROPHOTOMETRY. By Johanne Almer, Eleanor McAnsh, & Barbara Doupe. Centre of Forensic Sciences Ministry of Community Safety and Correctional Services, Ontario . INTRODUCTION.
By Johanne Almer, Eleanor McAnsh, & Barbara Doupe
Centre of Forensic Sciences Ministry of Community Safety and Correctional Services, Ontario
Colour can be a highly discriminating feature in forensic fibre comparison.
VIS microspectrophotometry increased the ability for colour discrimination.
Further discrimination can be obtained in the UV spectral range.
In this study, various aspects of UV-VIS microspectrophotometry were assessed to evaluate its use in a forensic laboratory for routine fibre analysis.
Same-day fibre analysis reproducibility
Day-to-day fibre analysis reproducibility
Spectral results from same-day
Spectral results from day-to-day
UV-VIS absorbance was measured through:
Absorbance spectra of mounting materials
UV-VIS absorbance was measured for white, non-dyed fibres of different polymer types:
Red wool fibre
Violet and white di-acetate fibres
Orange viscose fibre
Rust acrylic fibre
The microspectrophotometry of all coloured fibres can initially be done with XAM-mounted glass slides from 300-770nm with the UV-VIS system.
The need for re-mounting onto quartz slides for full UV-VIS analysis at 240-770nm depends on the fibre type and spectral results.
Fibres Mounted on Glass Slides MICROSPECTROPHOTOMETRY
Re-analyse Fibres on Quartz SlidesCONCLUSIONS
Nylons, Acetates, Modacrylic, Cotton, Ramie, Viscose, All other Acrylics, and Olefins
Silk, Wool, Acrylic with MVP, and Polyester
Absorbance at 300nm
> non-dyed referencepolymer spectra?